An automobile conventionally employs a hollow, tubular drive shaft to transmit torque from the transmission to the differential gears. Such drive shafts often produce annoying NVH (i.e., noise, vibration, and harshness). Accordingly, it is desirable to dampen NVH to provide for a quieter and smoother ride. Furthermore, it is desirable to prevent vibration to avoid mechanical failure from the loosening of assembled vehicle parts.
Several commonly assigned patents address NVH reduction. For example, U.S. Pat. No. 4,909,361 to Stark et al. discloses a drive shaft damper having a base tube or core formed of helically wound paper. A helical retaining strip, such as ethylene propylene diene monomer rubber (i.e., EPDM), is fixed to the core to engage the bore of the drive shaft.
Another example is U.S. Pat. No. 5,976,021 to Stark et al. U.S. Pat. No. 5,976,021 improves the drive shaft damper disclosed in U.S. Pat. No. 4,909,361 by including sealed ends and an innermost layer of waterproof material, such as aluminum foil.
Yet another example is U.S. Pat. No. 5,924,531 to Stark et al. U.S. Pat. No. 5,924,531 discloses a vibration damping shaft liner having a cylindrical core and a corrugated layer wound around the core in alternating helical grooves and flutes.
Each of the above-referenced patents is hereby incorporated by reference in its entirety.
The drive shaft dampers disclosed in the foregoing, commonly assigned patents are well suited for their intended purposes. That notwithstanding, there remains a need for drive shaft dampers that better reduce problematic NVH in particular drive shafts as installed in particular vehicles.